An aircraft moving through the air is often subjected to ice formation, and anti-icing or de-icing devices must be used to remove or prevent ice from accumulating on exterior surfaces of the aircraft. For any type of electrical heaters or de-icing heaters, the closer the heater is to the skin of an airfoil, nacelle, nosecone, engine cowl, or other aircraft part, the less power it takes to heat or de-ice the aircraft element due to the proximity of the heater to the external surface. Thus, aerospace applications of de-icing heaters attempt to place those heaters as close to the external surface, as possible. However, heaters used for de-icing on aircrafts are often subject to foreign object damage (FOD), such as hail, bird strikes, and other debris, particularly when those heaters are placed too close to the surface. Ideally, the heater uses minimal power to accomplish de-icing but is protected from FOD.
The materials used to protect heaters used for de-icing must be thermally conductive, allowing transfer of heat between the heater and the external surface of the aircraft element, but must also be electrically insulating to prevent shorting of the heater. Most thermally conductive materials are also electrically conductive, limiting the choice of materials.